Project Summary The perinatal period, from pregnancy through the first postpartum year, has important implications for women's health. Excessive gestational weight gain (GWG) is linked to deleterious health outcomes; yet most women exceed guidelines established for GWG, particularly women who begin pregnancy overweight or obese. These women are likely to remain overweight or obese at one year postpartum even if GWG is within guidelines and pregnancy-related weight gain is lost postpartum. Efforts to mitigate the health risks related to perinatal overweight can have substantial benefits for women's longer-term obesity and cardiometabolic health. To date, interventions to minimize excessive GWG alone have had limited impact. Some women may require continued intervention in the postpartum period to achieve optimal weight management. Alternatively, intervention delivered only postpartum may be sufficient to achieve a healthier weight at one year postpartum. It also is important to adapt intervention as women's needs vary over the course of pregnancy and postpartum. Accordingly, this application proposes a sequential multiple assignment randomized trial (SMART) to determine the efficacy of different intervention sequences during pregnancy, postpartum, or both. This non- restricted SMART also will allow us to investigate the impact of different combinations of intervention as a function of GWG. The proposed SMART is innovative as the first effort to evaluate different sequences of intervention across the perinatal period to mitigate maternal health risk by one year postpartum. Pregnant women (N=300), stratified by prenatal weight status (BMI=25-29.9 vs. ?30) will be enrolled at entry into prenatal care and randomized initially to intervention that addresses the challenges of weight and self-regulation during pregnancy (Health and Behaviors in Transition [HABITpreg]) or an educationally- enhanced treatment as usual (TAUpreg). At delivery, women will be re-randomized to a postpartum self- regulation intervention HABITpost or TAUpost. Women will complete assessments at a prenatal baseline, the end of pregnancy, and 6- and 12-months postpartum. The specific aims are to determine: (1) the combination of prenatal and postpartum lifestyle interventions that improves maternal weight, cardiometabolic health, depressive symptoms and stress at 12-months postpartum, and (2) evaluate the impact of combinations of interventions by GWG on maternal weight and health outcomes. We also will (3) examine the impact of pre- pregnancy weight status on the optimal sequence of interventions. For example, assignment to HABITpre followed by HABITpost may improve outcomes for obese women, regardless of GWG, whereas assignment to TAU followed by HABITpost may be needed for overweight women only when GWG is excessive. The proposed research is an extension of previous perinatal health research conducted by our investigative team, and will provide data on the selection and timing of behavioral interventions in the perinatal period to mitigate longer-term cardiometabolic health risks for women.